Oil filtering medium and method of preparing the same



Sept- 26, 1939- R. H. PENNEBAKER OIL FILTERING' MEDIUM AND METHOD OF PREPARING THE SAME Filed Sept. 26,1936 5 Sheets-Sheet 1 v INVENTOR ATTORNEY.

ggf??? Sept. 26, 1939.

R. H. PENNEBAKER OIL FILTERING MEDIUM AND METHOD 0F PREPARING THE SAME Filed Sept. 26, 1936 3 Sheets-Sheet 2 ATTORNEY.

Sept. 26, 1939; R. H. PENNEBAKER' OIL EILTERING MEDIUMAND METHOD OF PREPARING THE SAME Filed sept. 2e, 193e 3 Sheets-Sheet 3 Patented Sept. 26, 1939 UNITED STATES PATENT OFFICE N Robert H. Pennobakor, Memphis.- Tenn. Application September z8, 1936, Serial No. 102,762 s claim. (ci.` zio-iss) My invention relates broadly to an oil filtering medium and method of preparing the same and more particularly to an improved process of preparing and utilizing an oil filtering medium.

One of the objects of my invention is to provide a method of preparing an oil filtering medium and means for effectively utilizing such oil fltering medium.

Another object of my invention is to provide a l process of preparing a filtering medium by which the filtering medium maintains its eillciency over long' periods of time and is not subject to detrimental effects generally arising from free moisture. l Still another object oi' my invention is to provide an improved method of preparing a filtering medium by which detrimental effects o f free moisture may be eliminated,

A further object of my invention is to provide 2o a method of preparing fibrous materials for use in filtering systems by which the deliquescent properties -of fibrous materials are reduced and the eiiiciency of such fibrous materials as a filtering medium greatly increased by rendering such filtering medium substantially immune from conditions of humidity and free moisture.

A still further object of my invention is to provide a construction of oil filtering in which the number of oil filter units constructed in accordance with my invention, may be accommodated within casings adapted to filtration problems oi' various kinds.

Another object of my invention is to provide a construction of oil filter in which an oil filtering medium may be wrapped in a coiled layer on replaceable spool units interposed in the path of oil to be filtered.

Other and further objects of my invention reside in the construction of spirally wrapped replaceable filter units for oil filters as set forth more fully in the specification hereinafter following by reference to the accompanying drawings in which:

Figure l is a plan view of the replaceable filter unit showing the method of assembly of the filtering medium with respect to the spoolwhich carries the filtering medium; Fig. 2 is a horizontal sectional view taken on line 2-2 of Fig. 1; Fig. 3 is a central vertical longitudinal sectional v cw taken through a filter constructed in accordance with my invention and particularly adapted for association with the lubrication system of intornai combustion engines on automobiles; Fig. 4 is a fragmentary sectional view of the filtering unit taken on line 4 4 of Fig. 2; Fig. 5 is a sectional view on an enlarged scale showing the filtering medium and the arrangement of the screen for supporting the filtering medium; Fig. 6 is a detailed perspective view of a layer oi' the filtering medium and illustrating the support thereof by a 5 'screen like strip member; Fig. 7 is a central vertical longitudinal sectional view showing a filter constructed in accordance with my invention and adapted more particularly for industrial application; Fig. 8 is a horizontal sectional view taken on 10 line 8-8 of Fig. 7; Fig, 9 is a detailed side elevational view showing one of the spools upon which the screening member which supports the filtering medium is wound; Fig. 10 is a fragmentary sectional view of a modified form of filter em- 15 bodying my invention in which the closure for the outer casing is permanently united with the casing in instances where extreme economy in manufacture must prevail and in which the replacement of the filter units is not essential; 20.

Fig. l1 is a side elevational view of a larger form of filter constructed in accordance with my invention; Fig. i2 is a vertical longitudinal sectional view of the filter illustrated in Fig. 11; Fig. 13 shows still another modified form of industrial 25 type filterembodying my invention; and Fig. 14 illustrates one method which- I employ in maintaining the filter units in assembled v relation within the casing with the oil passages in the filter units maintained in alignment. 30

My invention is directed to a process of preparing a filtering medium and apparatus for efflciently employing the ltering medium thus prepared. I employ a ,fibrous material such as mineral or rock wool, silk, cotton, asbestos fibre and 35 thelike, and prepare this material for use as a filtering medium either alone or in combination with a filtering clay. It is necessary to, first, dehydrate the fibrous material by subjecting the material to a temperature high enough to drive 40 off the free moisture contained therein. It is impossible to keep such material from taking on a percentage of free moisture from the very moment the materials are manufactured until they are put into use. 'I'he percentage of free 45 moisture such materials absorb is determined entirely by climatic conditions to which the materials are subjected. This is true regardless of how the materials may be transported or what types of storage means may be employed. The 50 various types of activated earths which are suitable or rather most suitable for oil filtration purposes are really more sensitive to taking on moisture than some of the fibrous materials. Therevfore it is likewise quite necessary to dehydrate 55 these activated earths; namely fullers earth of different types, diatamaceous earths, bauxite and the like, before using them for filtering oil. In preparing the filtering medium of my invention, the materials are dehydrated to zero free moisture content (0 free moisture content) before they are used or combined to form the filtering medium and also before they are wetted with a light bodied, light colored, high quality mineral oil. This dehydrating of both the fibrous materials and the activated earths is a part of the process of the preparation of the oil-wetted materials either if used separately or in combination. The reason for oil-wetting any of the finely ground activated earths immediately after they are ground and dehydrated by the manufacturer is for the purpose of keeping them free of free moisture from the time they are manufactured until they are actually used regardless of the interval of time between their manufacture and consumption. This same thing applies to the fibrous materials, especially, for use in filtering lubricating oils.

The fibrous material in loose form is treated with the light-bodied and light-colored, high quality mineral oil by which the fibrous material becomes impervious to free moisture. When filtering clay or any of the several activated earths suitable for filtering oil is employed as part of the filtering medium of my invention, I finely divide the-filtering clay and thereafter treat the divided ltering clay with light-bodied. light-colored, high quality mineral oil. The fibrous material and/or the filtering clay after having been treated with the mineral oil is permitted to drain for allowing the excess oil to be separated therefrom. When I employ the fibrous material and the filtering clay in combination I mix the fibrous material and filtering clay either before or after the oil'treatment in proportions where the fibrous material greatly exceeds by both weight and volume the proportion of the filtering clay. I have found a proportion of three-fourths fibrous material and one-fourth filtering clay, by weight, to produce an excellent filtering medium.

The type of oil with which the materials are processed in a light-bodied, (that is the oil has a low viscosity of about seconds at 100 degrees F.) light in color (about 15 to 18 Robinson color) and having as high a flash point as possble. An oil with the above characteristics is an oil of very high quality and one which would not tend to lower the quality of any other average type motor oil or lubricating oil when in process of being filtered on most any type of mechanical equipment. Also another very desirable feature in this oil-wettedtype filtering mediumis the fact that when a filter is first started into service with the wetted-type medium the oil immediately begins to seep through every fraction of an inch of its surface area whereas, when using the drytype medium, invariably the filter is in service for many hours before the medium becomes entirely wetted and affords uniform seepage throughout its entire surface area. It is also my opinion from close observation that dry spots in this type of medium cause channeling of same,

which of course immediately permits unfiltered oil to pass through to the center outlet tube or duct and contaminate the entire volume of oil in the system.

After the fibrous material and/or filtering clay and/or the mixture thereof have been treated` by the light-bodied, light-colored, high quality mineral oil for reducing any deliquescent properties of the materials and rendering the materials impervious to moisture and after the excess oil is drained therefrom, I subject the oil treated ma- -terial to a compressing operation on a filter sup- The filter supporting surface porting surface. which I employ is a strip of metallic screening. The metallic screening provides a base or support for the filtering medium. The paste like substance constituting the filtering medium is spread upon the strip of metallic screen and is pressed thereon to insure intimate engagement between the filtering medium and the metallic screening. The filtering medium united with the supporting screen strip is now ready to be coiled or rolled into position on the supporting spool.

The supporting spool is an especially prepared device having a tubular central portion and a pair of end anges between which the screen strip carrying the filtering medium is wound. The central tubular portion of the spool is perforated and the perforated portion surrounded by a fine mesh screen such as 380 mesh screen adequate to allow the passage of ,oil or to prevent the passage of fine particles of filtering clay or fibrous material. The screen in. rolled form on the spool .provides means in various layers through the filtering unit for maintaining the filtering medium in proper position and also maintaining the porosity of the filtering medium for the passage of oil. The rolled filter unit is inserted within a filter casing of various forms and constructions and interposed in the path of the oil to be filtered. The filter unit effectively removes dirt, metallic particles, and other residue accumulated in a lubricant which tends to impair the operation of the filter. The filter units may be readily replaced when renewals are required as the structure of the device of my invention is very inexpensive in production.

Referring to' the drawings in detail the spool e constituting the support for the filter medium has end flanges I and tubular member 2 extend ing between the end flanges. Adjacent the con-V nection of the tubular member 2 with the end flanges l, I provide annular shoulders 3. The

annular shoulders are located intermediate the end flange I and the central tubular member 2.

from the perforated central tube 2 and allows passage of the filtered oil through the screen like tubular'member and through the perforations in the central tubular member while obstructing the passage of dirt, foreign matter, metallic particles and substances tending to impair the lubricating properties of the oil.

The filtering medium employed in the filter of my invention is shown at 1, spread in a paste like layer on the screen strip 6 which is rolled in position upon the spool like frame support. The end of the screen like strip 6 is spot welded or otherwise secured tothe end flanges i of the spool like frame support.

'Ihe filtering medium of my invention is pre- 2,178,978 pared as hereinbefore set forth by treating nbrous material such as mineral or rock wool, silk.'I cotton, asbestos fibre and the like and/or finely divided filtering clay such as'fullers earth, diatomaceous earth and bauxite which may b termed "actlvatedf earths, or mixtures of the said fibrous materialgand filtering clay, with a light-bodied, light-colored, high quality mineral 'oil. The quantities of the fibrous material and the filtering clay are selected sothat the fibrous material dominates by weight the quantity .of filtering clay employed. The mineral oil employed for wetting the fibrous material and/or the filtering clay is allowed to drain, and thereafter the paste like filtering medium is spread and pressed in position upon the screen strip l. The layer of filtering medium sl'own at l, supported by the screen like strip 8, is then rolled, coiled, or wound upon the spool like frame support so that a plurality of superimposed layers of the filtering medium are supported by the spool like frame support as illustrated in Figs. 2, 3, 4, 7, 8, 12, 13 and 14. The spool like support with the filtering medium wrapped thereon constitutes a filter unit which is insertable into an enclosing container of various constructions. 'Ihat is, the enclosing container may be shaped to meet the requirements of automotive lubrication, industrial lubrication or oil burner service and in other instances where oil must bey filtered. In Fig. 3 of the drawings, I have shown the filter unit of my invention as applied to an automobile type filter in which the filter unit is mounted in the enclosing container I0. An outlet -pipe connection II is provided for container I0 extending into the tubular upwardly extending outlet pipe 9 having the flanged end 9ah thereon. A gasket 8 is seated on the flanged end 9a of the tubular support and outlet pipe 9 and provides a seat for the lower recessed end of the filter unit. The upper recessed end of the filter unit is centered by means of a downwardly projecting central tubular member 22 integrally connected with the top closure I1 for the container. The top closure Il is shaped to fitover container Iii and to be supported by the fiat peripheral flange I8 thereon with` an annular shoulder I8 depending from top closure I1 and extending within container I0. A gasket I9 is provided for sealing the Joint b etween the periphery of top closure I l and the peripheral flange I3 on container I0. Bolts 20 extend through top closure Il and through gasket I9 and peripheral iiange IB and are secured by washer and nut connections 2i beneath the peripheral flange I6. Depending upon whether or not the discharge connection is provided adjacent the top, or the bottom of the filter container, I provide a removable plug 23 adapted to be screw threaded into the central tube 22. Plug 23 closes top 22 so that the dischargeconnection is taken through tubular support 8. 'I'he discharge connection is shown extending from outlet pipe connection I I through coupling I2 to the outlet pipe I4 of the oil system. A removable plug I5 is provided in the base of container ID for draining sediment from the container from time to time. The-oil inlet is' indicated at 24 in the top closure I1. 'Ihe oil enters oil inlet pipe 24 and seeps in a radial direction through the superimposed layers of filtering medium constituted by the wrapped paste like layers of filtering medium supported on the spool like frame. The fact that the filtering medium is divided into layers with spaced layers of screen like material resisting ollas a result of Y used filter unit therebetween insures against breakdown of v 3 the filtering medium for developing crevices or channels through `which oil 'might tend to pass instead of seeping through the filtering medium. Any crevices or channels which tend to develop are self-sealing between the spaced layers of screen like material by which the paste like filtering medium is supported. moisture on the filtering tialiy nil inasmuch as the filtering clay Vare protected. by a film of moisture initial oil treatment to which the filtering medium is subjected.

'Ihe niter unit may be removed from time to time by removing closure I1. withdrawing the and inserting a fresh filter unit.

In certain oil systems greater oil filtering capacity is necessary whereupon I-employ an enlarged lcasing I Il as illustrated in Fig. 7 and arrange the filter units" in cascade or in superimposed relation one above another. In this arrangement the filter units are mounted end to end with a coupling tube 25 therebetween. The coupling tube 25 is seated against gaskets 8 mounted in the upper recess of the lower filter Detrimental effects of medium are substanunit and the lower recess of the upper vfilter unit and serves' to establish a continuous passage for oil through the central tubular member'. The tubular recess of the tubular filter unit is arranged to receive a coupling tube 28 which seats against gasket l, retained in the upper recess of the upper filter unit and against the gasket 8 seated in the central depending tube 22 in top closure I1. In this arrangement the lower tubular support B and the coupling tubes 25 and 26 are vso dimensioned that the two filter units may be properly assembled in superimposed relation. However, there are instances in` which inaccuracies may result in a loose fit ofthe superimposed filter units in which event I provide adjacent the closed end of the filter units an adjusting screw as illustrated for example in Fig. 14.

'I'he end oi' the filter which is to be maintained normally closed has the end of the adjacent filter unit plugged by a disc like member 39 which seats against gasket 8 and provides a bearing against which the adjusting screw 40 bears. The adjusting screw Iii has the end 4I thereof in contact with disc 39. The end 4I is forced against disc 39 by applying a tool to the tool engaging head 42 by which the entire column of the filter units may be tightened in a rigidly erect position. As heretofore pointed out the adjusting screw may be mounted in the tubular support and outlet pipe 9 if the discharge end of the filter is to be taken from the top of the filter. In this instance the screw ,40 is somewhat longer than the length of the screw required in the top closure I'I. The same manner of sealing the end of the central oil passage is employed by utilizing a. disc 39 seated against a gasket 8 retained in the recessed end of the lter unit. It will be understood that the 'adjusting screw structure may be employed in many of the forms of my invention which I have illustrated.

In automotive type filters it is often desirable to manufacture'one.type oi" filter which is extremely low in cost. In such instances I may seal a filter unit directlywithin the casing I Il in the manner illustrated in Fig. 10 where a cover 30 having a rolled over annular skirt 3i is en gaged beneath the periphery of beaded edge 21 of the container Iii. The beaded edge 21 of container I0 may have an annular recess 28 therein for receiving a resilient gasket 29 which serves to provide a substantially hermetic seal between fibrous material and mobile and when the filtering efiiciency thereof has become impaired the entire casing with the filter unit therein may be removed and replaced by an entirely new casing with a .filter unit contained therein.

In applying my invention to industrial installations I find that slight changes in form of assembly of the filter becomes necessary. In Figs. 11 and 12 I have shown one industrial type filter in which a casing 32 which is substantially a complementary counterpart of casing I0 is employed. That is, casing 32 is inverted in position with respect, :to` casing i0. Casing 32 has an annular flange 33 thereon which is substantially aligned with annular flange I8 of casing i0 with gasket I9 disposed therebetween. Bolts extend throughthe annular ange 33, gasket i9 and iiange i8 and are secured by bolt and nut connections 2li-2|.

provides both a support and which may provide a passage for oil for the oil filter units is shown in Fig, 12 at 35 depending from the end of casing 32. Plug 36 serves to close the end of tubular member if the discharge end of the filter is to be located at the bottom of the filter. Tubular member 35 is provided with flange 35a which seats against gasket 8 inthe recessed end of the upper filter unit for assembling the filter units within the casing and maintaining the position thereof. The coupling tube' 25 heretofore described in connection with Fig. 'l serves to interconnect the upper and lower filter units, when thefilter units are assembled as shown in Fig. 12.

In other industrial installations it is necessary to further increase the capacity of the oil filter. Under these circumstances I employ a construction as illustrated in Fig. 13 wherein casing I0 is lengthened and the complementary counterpart thereof indicated at 32 also lengthened to provide closure means for at least two filter units constructed in accordance with my invention. 'The filter units are assembled in superimposed relation with coupling tubes 31, 25 and 38 arranged in suitable relation to gaskets 8 and disposed in adjacent recesses formed in the ends oi the filter units. The coupling tubes serve to maintain the alignment of the longitudinally extending oil passages through the several filter units. Proper -tensioning means of the kind such as illustrated in Fig. 14 maybe employed in maintaining the alignment of the filter units.

The manner of preparing the filtering medium of my invention insures against detrimental effects of moisture which heretofore has been a serious defect in the operation of oil filters. The arrangement of oil filter units as set forth herein is highly practical in that each unit provides a radially inward path for the seepage of used oil allowing dirt, foreign matter, metallic particles and other accumulated matter to be removed from the oiland the oil ldelivered to the central discharge duct. As pointed out, inlet and discharge connections may be at the same end of the filter casing or at opposite ends in accordance with the most convenient installation arrangement for the llter.

While I have described my invention in certain of its preferred embodiments, I realize that modifications may be made and I desire that it be understood that no limitations upon my in- The inlet for oil in casing 32 is indicated at 34. 'I'he tubular member which vention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A'filter unit for oil comprising a spool like frame having a pair of end flanges interconnected by a central tubular member. said centrai tubular member being perforated for the passage of oil therethrough', a filter screen mounted concentrically about the perforated central tubular member, a screen like supporting strip having a paste like filtering medium spread thereon and consisting of a mixture of fibrous material and finely divided clay wetted by a light-bodied oil, said 'screen like strip with the paste like filtering medium thereon being spirally wrapped about said filter screen for providing a plurality of superimposed layers of filtering medium on said lter unit, said paste like medium penetrating the meshes of said screen like strip and uniting adjacent layers of said medium to provide a `substantially homogeneous filtering mass over said filter screen.

2. A filter unit comprising a spool like frame support having a pair of end flanges interconnected by a central tubular member, said central tubular member having an annular shoulder formed thereon adjacent the inner faces of each of said end flanges adapted to receive supporting fluid conduits, and said central tubular member being perforated for the passage of fiuid therethrough,a tubular screen like member supported between the annular shoulders on said central tubular member, a filtering medium spread in paste like form upon a flexible screen like strip and spirally. wound around said tubular screen like member and providing a multiplicity of superimposed layers of filtering medium for fiuid passing radially inwardly to said central tubular member. f

3. A filter comprising a casing, a plurality of filter units adapted to be disposed in superimposed relation within said casing, each of said filter units having a passage extending longitudinally therethrough and each of said units be- 'site ends of each unit, coupling members extending between the recessed portions of adjacent filter units, and means extending into the recessed portions of the filter units on the extreme opposite ends of the superimposed series of lter units for supporting said series of units and maintaining the passages in said filter unitsin axial alignment. y

4. A filter comprising a casing, an inlet connection for said casing, acentral discharge connection in one end of said casing,l a tubular member projecting interiorly of said casing from said central discharge connection, a flanged end on said tubular member, a multiplicity of` filter units each having longitudinally extending passages therethrough and Aeach being recessed at the opposite ends thereof, the recessed end of one of said filter units being removably seated on the flanged end of said tubular member with the passage in the last mentioned filter unit aligned with the dis'charge connection, means .for aligning the passages in the other filter units with the passage, in the last mentioned filter unit, and means for closing the opposite end of said aligned passages and clamping said units in position.

5. A filter comprising a casing, a multiplicity of filter units adapted to be mounted in superimposedA relation within said casing, a passage als aligned with said discharge duct, an inlet ,con-

nection tor said casing whereby tluidto be 111- -tered is directed radially inwardly through cach of said lter umts and delivered to said discharge duct, meansfor closing the end oi `said discharge duct opposite the discharge end thereof, and means bearing on said closing means for adjustably tensioning the interiitting relationship of the said superimposed oil niter units for maintaining said units in position.

6. A illter unit for oil comprising a spool-like carrier having a perforated central tubular memperi'orated tubular member. a iiltering medium carried by said spool-like carrier comprising a mixture of fibrous material and nely divided clay, said screen being adapted to retain said clay and said fibrous material, said 'ltering medium being -wetted with a light-bodiedl oil, and a screen-like strip spirally disposed in said ill- -tering medium about said tubular member for supporting said iiltering medium in a tightly packed arrangement, the wetted condition of said filtering medium aiding it to unite through the meshes of said screen like strip, preserving it from deterioration prior to use and rendering it immediately penetrable by the oil to be illtered.

ber, a fine meshl screen carried by said 

